The present invention relates to an arm rotating device having an arm with a free end and a fixed end and rotatably supporting the arm around a support post that is fixed on the side of the fixed end, the arm being configured to enable an operating body, such as an operating device and a display operating device, to be mounted on the side of the free end, and also relates to an image forming apparatus provided with such an arm rotating device.
An exemplary operating portion of an image forming apparatus includes a display operating device in which a touch panel is arranged on a surface of a display that displays an operating state and the like of the apparatus. In recent years, in accordance with multi-functionalization of image forming apparatuses, the amount of information to be displayed has increased and thus a display and a touch panel have become large in size. In addition, due to the enlargement of the size of a recording medium that can be subjected to an image forming process or diversification of processes to a recording medium, a feed path has become longer, so that the standing position of an operator to an image forming apparatus has not been fixed.
For this reason, for example, as disclosed in Japanese Patent Laid-Open Publication No. 2011-081059, some conventional image forming apparatuses are configured to rotatably support a display operating device with respect to the apparatus through an arm and a support post and enable the display operating device to be operated in an arbitrary position within a predetermined range. The display operating device receives a pressing operation by an operator in a switch arranged in the front face of the display operating device, or from a touch panel on the surface of a display.
As the arm becomes larger to cope with the increase in weight associated with the enlargement of a display, the pressing operation of the touch panel has easily generated vibration in the display operating device. In order to suppress this vibration, as the easiest way, measures in which a coil spring is wound around the peripheral surface of the support post and a load is applied to the rotating operation of the support post by the elastic force of the coil spring have been taken.
However, while the load to be applied increases as the arm becomes larger, if the winding force of the coil spring to the peripheral surface of the support post is increased, scraping occurs in the peripheral surface of the support post and the internal peripheral portion of the coil spring due to the repetition of the rotation of the arm and thus the load to be applied to the support post may be decreased. In addition, if the winding force of the coil spring is made too large, the load to the support post may be greatly decreased due to the error of component precision or assembly precision.
In any case, the decrease in load to the support post raises a problem that interferes with the pressing operation of the display operating device. This problem occurs similarly when an operating device other than the display operating device is mounted on the side of a free end of the arm.
An object of the present invention is to provide an arm rotating device capable of preventing a load to a support post from being decreased by causing a biasing force in a direction in which the elastic force of a coil spring is increased to be constantly applied to at least one end of the coil spring that is wounded around the support post and also capable of exactly performing a pressing operation with respect to an operating body, and to provide an image forming apparatus provided with such an arm rotating device.